A tiltrotor aircraft may include two or more rotor systems that can be rotated between an airplane mode and a helicopter mode. In the helicopter mode, the rotational axes of the rotor systems are in an approximately vertical position to generate aerodynamic lift to support the weight of the tiltrotor aircraft in flight and to generate thrust to move the tiltrotor aircraft in forward flight. In the airplane mode, the rotational axes of the rotor systems are in an approximately horizontal position so that the tiltrotor aircraft behaves similar to a fixed-wing aircraft. The rotor systems may be controlled by a control system to stabilize the tiltrotor aircraft and reduce workload by assisting the pilot.